One of the guys at the Fort Worth Library Panther Lab Maker Space recently showed off a very cool method of storing the resistors in his electronics supplies. He uses a sewing kit with an array of small, individual boxes which close securely, one box for each size resistor(For the uninitiated, those plastic boxes with "configurable" compartments are terrible for electronic parts. The walls are never flush to the bottom of the box, so whenever you pick it up stuff slides beneath walls and gets all mixed up.)

I scoured the sewing stores nearby but couldn't find the same organizer. Merry picked up some clearance fabric, but that wasn't really in the success criteria for the mission. I did find those storage systems on Amazon but they were over $50. I didn't want to pay that and wait two days for shipping when I could design my own solution and, well, wait two days for it to print.

I had these plastic test tubes (okay, they're pin holders, but "test tube" sounds more technical) and decided to build a rack that could organize them. First step was a single rack, modeled in OpenSCAD. Couple of key criteria: first, the seat at the bottom and the collar slightly above needed to hold the tube in place when turned vertically, yet the collar has to be low enough that the tube can tilt and be extracted even when there's a row above. Second, I needed enough space for my fat fingers to get hold of these things. And third, I want to be able to connect any number of holders to accommodate whatever size box I find for them.

I did make a 5-holder version once I was happy with the single. It's pretty easy in OpenSCAD; there's a module for a single holder. Call that module five times with a few translate tatements and you're good to go.

The connector holes are 2mm diameter, so the knobs on the connector straps are slightly smaller -- 9.25mm at the base and 9mm at the tip. (The width of the strap is also a pressure fit, since the recess is 10mm wide and the strap itself is 10mm wide. Yeah, probably should have made the strap just a tad more narrow, but hey -- it pressure fits.)

Next step, of course, is to find or print a box to carry these in, or perhaps print something to mount them on the wall in the electronics lab/office/game room.